<p>5xxx series aluminum (Al) alloys are recommended over the other wrought aluminum alloys for their relatively better weldability; however, some studies reported serious cracking in these alloys during welding. The weldability of these alloys has been investigated both experimentally and theoretically with respect to solidification cracking susceptibility to provide better understanding of these materials. The transverse motion weldability test was used to assess the crack susceptibility of 5086 and 5456 Al alloys which were welded by tungsten inert gas (TIG) welding. The crack susceptibility predictions of the tested Al alloys were made using the recently proposed cracking index. The consistency between the test results and the predictions helped verify the simulation parameters used to calculate predictions for TIG welding. Based on the test results of the Al alloys and the identified simulation parameters, the crack susceptibility predictions of binary Al-magnesium system were discussed to help design new alloys and welds to avoid solidification cracking.</p>